To set up a new Microsoft Office, you may require an active internet connection and needed space within your disk. Let’s take a look of that one by one in a sequence:
When you go to the office setup page, it asks you to sign-in. Sign In with your Microsoft Account, If you do not have one, you can always create one.

After signing in, you need to enter your product key. If you don’t have a product key, you have buy one at www.office.com. You have to buy Microsoft Office to continue further.

After entering a product key, It will take you within your Microsoft Office product page.

In that portal, it gives you two option. To work online within that portal or to download and install Microsoft office.

To download Microsoft Office on PC, you have to click on Orange “Install Office” button on the extreme right corner of the window. When you click on that button, your download will start.

After the download completes, open and run that downloaded installer file.

A window appears on your display screen. Click on Install Office.

You will get a prompt on your computer. You need to allow and give permissions to install it on your Operating System. In some case like that of Mac you will get a prompt which requires password.

On the prompts are accepted, Installation Process is started.
www.office.com/setup
www.office.com/setup
www.office.com/setup
www.office.com/setup